Conventionally, in a graphical user interface, hereinafter simply referred to as “GUI”, utilizing a pointing device such as a mouse to operate a pointer in a GUI display screen to select a button region or a slide bar region and execute functions associated with the afore mentioned region is widely practiced. In a GUI such as that described above, in order to prevent erroneous operation by the user, a method is known in which a dialog box is displayed to obtain user confirmation when a button that should be protected has been pushed. However, in the method in which a dialog box is displayed to obtain confirmation from the user, the dialog box is displayed in response to the user operation of the button, and because the user is requested to select “Yes”, “No”, or “Cancel” as a response to the message shown in the dialog box, the operational flow tends to be interrupted. Furthermore, since space on the display area is required to display the dialog box, and when there is not ample space on the display area, there are cases in which the buttons that should be operated are covered and thereby hidden by the dialog box.
A method for preventing erroneous operations by the user by changing the display characteristics of the display of the region so as to enable the user to discriminate whether or not it is possible to execute the function associated with the the aforementioned region is described in Patent Reference No. 1.    Patent Citation 1: Japanese Unexamined Patent Application, First Publication No. H10-198545